Interesting -- a truly exhaustive (and exhausting!) analysis.
It seems to me, though, that there should be a materialism other than what you're referring to as Type A and Type B, and an example of that would be the assertion that the experience of qualia is itself a material phenomenon, required for the functioning of a particular kind of mechanism (i.e., in that kind of conscious mechanism, such an experience would be causal -- both caused and causing). If this were the case, then it would seem to make no more sense to say we can "conceive" of a philosophical zombie than it would to say we can conceive of a kind of zombified car in which every material part functions exactly as it does in the normal car, but in which the rotation of the drive shaft, say, is without causal effect. (Or, perhaps closer, in which the drive shaft is simply missing, but that of course would contradict the assumption that every material part functions the same.)

I've put a new paper online: "The Two-Dimensional Argument Against Materialism". An abridged version is forthcoming in the Oxford Handbook of the Philosophy of Mind (edited by Brian McLaughlin), and the whole thing is forthcoming in my book The Character of Consciousness, to be published next y...